This invention relates generally to wrapping machines utilizing film to package articles supported on trays and, more particularly, to a modified film wrapping machine wherein film drawn into the machine to wrap a package is extended to permit the wrapping of oversized packages which could not otherwise be accommodated by the wrapping machine.
A variety of film wrapping machines are known in the prior art. In modern wrapping machines, multiple film widths and lengths are used to wrap trayed commodities. For example, one commercially available machine includes a sensing system which determines the length and the width of a trayed commodity to be wrapped. Based on the sensed length and width dimensions the wrapping machine selects one of two differing width film rolls and the length of the film sheet drawn from the selected roll. Such a machine is fully described in U.S. Pat. No. 4,510,731 entitled "Film Wrapping Machine Including Film Length Selection," which is assigned to the same assignee as the present application and is incorporated herein by reference.
The wrapping machine disclosed in the referenced patent can wrap a large variety of packages having base dimensions which vary from approximately 5 inches by 5 inches to approximately 9 inches by 12 inches by selecting the appropriate width and length of film to be wrapped about the package. However, the maximum size package which can be wrapped in the machine is limited by the width of the package handling path through the machine and/or the width and length of the film which can be drawn into the machine to wrap a package. Larger packages having one dimension which exceeds 12 inches and referred to herein as family sized packages or "family packs" cannot be satisfactorily wrapped by the wrapping machine and must be wrapped on another machine or be manually wrapped.
Most wrapping machine users cannot afford or justify two wrapping machines, and manual wrapping is inconvenient and can be tolerated only as long as relatively few family sized packages are to be wrapped. However, in this time of heightened consumer awareness, family sized packages which hold larger quantities of products oftentimes on sale at an attractive price are in great demand and can require that large numbers of such packages be wrapped.
It is apparent that the existing wrapping machine could be widened to expand the package handling path and permit wider film to be used such that family packs could be accommodated by the wrapping machine. However, such modification requires the replacement of a large portion of the wrapping machine and, hence, is expensive.
Alternately, adjustments to the film pulling apparatus or replacement of the film pulling apparatus to provide extended film draw are possible. With extended film draw, family packs can be accommodated by feeding such packages into the machine lengthwise rather than widthwise as is normal. While such an approach may be more attractive than widening the package handling path of an existing machine, it still requires the replacement of a substantial portion of the machine or repeated adjustments to the machine such that it can accommodate both the existing range of package sizes and the larger family sized packages.
It is, thus, apparent that the need exists for an improvement to existing film wrapping machines such that family sized packages can be wrapped. To be practical, the improvement cannot require extensive changes to the wrapping machines and cannot disrupt the normal operation of the machines which is required to wrap the majority of the packages.